Pressure transmitter selection considerations - Database & Sql Blog Articles

Among the many types of instruments, transmitters are the most widely used and commonly found in industrial applications. Transmitters can generally be categorized into several types, including pressure transmitters and differential pressure transmitters. They are frequently used to measure pressure, differential pressure, vacuum, liquid level, and other physical parameters.

Transmitters come in different configurations such as two-wire (current signal) and three-wire (voltage signal) systems. Two-wire transmitters are particularly popular due to their simplicity and reliability. Additionally, there are both intelligent and non-intelligent models, with smart transmitters becoming increasingly common. They can also be either pneumatic or electric, with electric transmitters being more prevalent in modern systems.

Moreover, transmitters are available in intrinsic safety and explosion-proof versions depending on the application environment. When selecting a transmitter, it's important to choose the right type based on your specific needs and operational conditions.

1. Compatibility with the Measured Media

When choosing a transmitter, it's crucial to consider the compatibility between the media being measured and the transmitter’s components. Pay attention to the pressure interface and the materials used for the sensitive elements. If not properly matched, the diaphragm may corrode quickly, leading to equipment failure or even personal injury. Therefore, material selection is a key factor in ensuring long-term performance and safety.

2. Impact of Medium and Ambient Temperature

The temperature of the medium being measured and the surrounding environment should be taken into account during selection. If the operating temperature exceeds the transmitter's compensation range, it may cause measurement drift. To avoid inaccuracies due to temperature sensitivity, always ensure that the transmitter is suitable for the actual working conditions.

3. Selection of Pressure Range

When selecting a transmitter, consider the working pressure level of the system. The pressure range of the transmitter must match the application requirements to ensure accurate and reliable measurements without overloading the device.

4. Selection of Pressure Interface

During the selection process, make sure to use the correct pressure interface size as specified by the user. Choose the appropriate thread connection type and verify the product drawing. If needed, the manufacturer can provide samples for confirmation.

5. Selection of Electrical Interface

It's essential to confirm the user’s signal acquisition method and field wiring setup. Ensure that the sensor signal is correctly connected to the user’s interface. Selecting the right electrical interface and signal mode is critical for proper operation and data accuracy.

6. Selection of Pressure Type

Pressure gauges can be classified based on the type of pressure they measure. An instrument that measures absolute pressure is known as an absolute pressure gauge. Most industrial pressure gauges measure gauge pressure, which is the difference between absolute pressure and atmospheric pressure. When the absolute pressure is higher than atmospheric pressure, the reading is a positive gauge pressure. If the absolute pressure is lower than atmospheric pressure, the reading becomes negative, referred to as vacuum pressure. A meter that measures vacuum levels is called a vacuum gauge.

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